package com.mccree.websocket;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.stream.ChunkedWriteHandler;

public class MyServer {

    public static void main(String[] args) throws InterruptedException {
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup,workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline pipeline = ch.pipeline();
                            pipeline.addLast(new HttpServerCodec());
                            pipeline.addLast(new ChunkedWriteHandler());
                            /**
                             * 1. http数据在传输过程中是分段, HttpObjectAggregator ，就是可以将多个段聚合
                             * 2. 这就就是为什么，当浏览器发送大量数据时，就会发出多次http请求
                             */
                            pipeline.addLast(new HttpObjectAggregator(8192));
                             /**
                                说明
                                1. 对应websocket ，它的数据是以 帧(frame) 形式传递
                                2. 可以看到WebSocketFrame 下面有六个子类
                                3. 浏览器请求时 ws://localhost:7000/hello 表示请求的uri
                                4. WebSocketServerProtocolHandler 核心功能是将 http协议升级为 ws协议 , 保持长连接
                                5. 是通过一个 状态码 101
                             */
                            pipeline.addLast(new WebSocketServerProtocolHandler("/hello"));

                            pipeline.addLast(new MyTextWebSocketFrameHandler());

                        }
                    });

            ChannelFuture future = serverBootstrap.bind(7004).sync();
            future.channel().closeFuture().sync();
        }finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}
